Nicola Sturgeon learned of SNP MP allegations from Sunday newspaper
Scotland's First Minister Nicola Sturgeon said the first she knew about claims surrounding an SNP MP was when she read them in a Sunday newspaper.
Police are looking into alleged irregularities with property transactions carried out on behalf of Michelle Thomson.
Ms Sturgeon said the matter deserved investigating.
Ms Thomson, who is MP for Edinburgh West, has denied any wrongdoing but has withdrawn from the party whip.
The first minister was asked by journalists at Holyrood to comment on the case.
Ms Sturgeon said she could not speak about Ms Thomson's business practices, adding that it was "not a situation she would have chosen to have".
The SNP leader said her party did not know about the allegations until they were revealed by The Sunday Times.
The police probe was prompted after property transactions in 2010 and 2011 led to solicitor Christopher Hales being struck off by the Law Society of Scotland.
It referred the case to the Crown Office, which has instructed the police investigation.
The BBC understands the initial inquiries will not involve Ms Thomson, who was the party's business spokeswoman at Westminster.
The 13 transactions that led to Mr Hales being struck off all involved Ms Thomson or M&F Property Solutions, a firm in which she was said to be a partner of.
After a hearing in May 2014, the Scottish Solicitors' Discipline Tribunal said Mr Hales failed to provide mortgage companies with key information used to prevent fraud and must have been aware that there was a possibility he was facilitating mortgage fraud, whether or not it occurred.
The Law Society said it first raised the case "informally" with the Crown Office in December last year but then made a formal referral in July 2015.
Business for Scotland
In a statement released on Tuesday evening, Ms Thomson said she would "cooperate fully" with the police inquiry if she was required to do so.
She added: "I have always acted within the law and look forward to being cleared of any wrong doing.
"I have this afternoon decided to withdraw from the party whip whilst an investigation takes place.
"Once the investigation is concluded I look forward to returning to play a full role in party activities."
Her withdrawal from the whip means she is no longer a member of the parliamentary party and will not speak for the SNP on business issues at Westminster.
An SNP spokesman said, in line with party rules, her SNP membership had also been suspended.
Ms Thomson was a leading figure in the pro-independence group Business for Scotland before she was elected an MP in May.